Space band cleaning machine



I Sept. 26, 1961 M. H. HARTZELL 3,001,216

SPACE BAND CLEANING MACHINE Filed May 25, 1959 7 Sheets-Sheet 1 @Z' INVENTOR.

Sept. 26, 1961 M. H. HARTZELL SPACE BAND CLEANING MACHINE 7 Sheets-Sheet 2 Filed May 25, 1959 INVENTOR.

P 1961 M. H. HARTZELL 3,001,216

SPACE BAND CLEANING MACHINE Filed May 25, 1959 7 Sheets-Sheet 3 IN V EN TOR.

AHOEN Sept. 26, 1961 M. H. HARTZELL SPACE BAND CLEANING MACHINE 7 Sheets-Sheet 4 Filed May 25, 1959 I/l/ 'IlIIlI/IIII INVENTOR.

Sept. 26, 1961 M. H. HARTZELL SPACE BAND CLEANING MACHINE Filed May 25, 1959 7 Sheets-Sheet 5 INVENTGR.

Sept. 1961 M. H. HARTZELL 3,001,216

SPACE BAND' CLEANING MACHINE Filed May 25, 1959 7 Sheets-Sheet 6 I I L A A P 1961 M. H. HARTZELL 01,

SPACE BAND CLEANING MACHINE Filed May 25, 1959 7 Sheets-Sheet 7 75 47 5 25' 17 22 o0oo0oooo@0o' o 9a 3/ o 1 0 O O O INVENTOR.

AWM?

rates Filed May 25, 1959, Ser. No. 815,500 17 Claims. (Cl. 15--77) This invention relates to a of the chain operated type.

In previous chain type machines a pair of parallel chains for carrying the bands through the cleaning operation required an independent reciprocating mechanism for feeding bands to the chains that entailed an interrupted movement of the bands, as well as involving other complications that were either expensive to manufacture or had certain limitations of operation.

(lertain objects of my invention, either singly or collecttvely, and to provide an improved chain type space band cleaning machine that is relatively simple in construction, operation and maintenance, that insures efficient feeding of the space bands from a stack with minimum possibility of feeding two bands at one time such as has heretofore occurred when a band is damaged or excessively worn, that will more effectively scrape off typographical metal Which normally adheres to a localized area of the band and particularly to do so with minimum wear and tear of the overall band surfaces a large portion of which is unaffected by the typographical metal, that will provide in a simple manner localized scraping and polishing pressure on the band at its critical area as the band passes through its cleaning operation, and that will effectively discharge the hands into a receiver.

A further object is to provide an improved chain type space band cleaning machine that eliminates the need for an indepndent feeding mechanism and is adapted to provide a smooth uninterrupted movement of the bands as they flow from a supply magazine, this being accomplished by having elements so combined that the chain mechanism is adapted in one continuous operation to elfectively feed the bands from the magazine and carry them through the cleaning operations into a receiver.

Still another object is to provide improved means whereby space bands of different thicknesses may be effectively cleaned.

Other objects and advantages will be more apparent to those skilled in the art from the following description of the accompanying drawings in which:

h FIG. 1 is an overall perspective of my improved mac me;

FIG. 2 is a longitudinal section through the machine to show the general arrangement of parts with certain elements omitted for clarity;

FIG. 3 is an enlarged fragmentary perspective of a group of space bands as they would be stacked in the feeding chamber or magazine but with the chamber walls and other elements omitted for the sake of clarity;

FIG. 4 is a fragmentary perspective near the feeding end of the machine to show particularly my improved single chain mechanism together with one of the band carriages thereof;

FIG. 5 is an enlarged perspective of the band carriage for feeding the bands and supporting the same at a localized area during cleaning;

FIG. 6 is a fragmentary perspective showing the guide- Ways for the band carriage but with the chain removed;

FIG. 7 is an enlarged longitudinal sectional view showing a band being carried through the scraping and polishing block section of the machine;

FIGS. 8, 9 and 10 are enlarged fragmentary sectional views at the feeding end of the machine to show successive stages of feeding a band;

FIG. 11 is an enlarged fragmentary sectional view to show the preferred arrangement of inclining the space ted space band cleaning machine ice bands in the feeding chamber whereby I am able to minimize the possibility of feeding more than one band at atime;

FIG. 12 shows the bands in an extreme inclined position in the feeding chamber, this for the purpose of illustrating most strongly the feeding principle involvedwith inclined bands; 7

FIG. 13 illustrates that my improved machine may have the bands positioned horizontally in the feeding magazine although this has certain undesirable limitations;

FIG. 14 is a perspective of the scraping and cleaning block section looking upwardly from the bottom thereof;

FIG. 15 is an enlarged perspective of the chain with a space band being fed thereby together with a portion of the chain guideway;

FIG. 16 is a cross sectional view taken substantially on the line 16-16 of FIG. 15;

FIG. 17 is an enlarged perspective view of the receiving chamber and a portion of the chain and sprocket adjacent thereto;

FIG. 18 is a longitudinal sectional view showing the space band carriage initially discharging a space band into the receiver;

FIG. 19' is a similar view showing the band further progressed in its feeding movement into the receiver, and

F 1G. 20 is a diagrammatic view showing how the bands are initially moved into the receiving chamber.

In the particular embodiment of the invention which I have shown herein merely for the purpose of illustrating one specific form thereof, I have provided a feeding section generally indicated at 1, a cleaning section 2 for scraping and/or polishing bands, and a receiving end 3 all mounted upon a frame 4, preferably sheet metal, having sides 5 and end pieces 6. A pair of shafts 7 and 8 are journaled in the frame to support sprockets 9 and 10 around which a single endless chain 11 travels. As shown in FIGS. 15 and 16 the upper portion of the chain loop rides on a cross member 12 which in turn is secured to vertical guide, wall members 13 to form a chain groove generally indicated at 14. The chain guiding unit 12, 13 is supported by the side walls 5 of the frame and held thereto by screws 16, FIG. 1, extending into the members 13. i

The single chain functions as part of my improved feeding means. The bands such as shown at 18, FIG. 3, are stacked between sidewalls 19 of the feeding magazine 1, and as is well known the bands consist of a relatively long body section 19 tapered from a thick rear end at the left and is provided with a slot 20 near its forward thin end which is closed by a cross piece 21, FIG. 1'1. A sleeve portion 22, longitudinally guided in the slot 20 and overlying the tapered body is provided with lateral ears 23. These ears are supported upon raised pins 24 and 25 while the rear portion of the stack of bands is supported upon a depressed block 26, FIG. 4, disposed generally in the groove 14 of the chain guide sides 13. The stack of bands is held in its longitudinal position by a weight 29 suitably vertically guided in the forward end of the magazine Walls 19. This weight is V-shaped in cross section along its left vertical edge was to be received within the V-shaped opening 30, FIG. 15, of the band sleeve. The lowermost band is adapted to lift this weight during discharge of such band.

In order to feed the bands and continue their movement through the scraping and cleaning steps and to discharge the hands into the receiver in one continuous operation by the single chain 11, I have provided the chain with a series of carriages generally indicated at 31, FIGS. 2 and 6, suitably spaced so as to receive successive bands. These carriages are linked into the chain by chain pins 32 and are guided against vertical displacement :by laterally feeding chamber.

gradually directed into its precision guided position by first riding up on a curved surface d2, FIG. 7 and thence along a depressed surface 4-3 and thence over a slightly upwardly inclined cam-like surface 44 on to a higher horizontal surface 45. The plate 12 is provided with a narrow slot 46 to receive the sprocket 7 while the portion of plate 12 adjacent to the slot is capable of supporting the chain links and carriages as shown in cross section in FIG. 11. To feed the bands the carriage is provided near its trailing end with an upwardly extending lug 47 which as shown in FIG. 8 is high enough to engage the back edge 49, FIG. 15, of the space band sleeve 22. As shown in FIG. '8 the feeding lug initially engages the sleeve edge slightly below its upper surface. However, as the sleeve (and band body) is moved forwardly to the right the sleeve ears will be moved off of the pins 24 and 25 as shown in FIG. 9. As the band drops, the sleeve moves further down over the lug 47 thereby insuring a full positive engagement with the bandto carry it with sufiicient force through subsequent scraping and polishing operations.

- The principle of having the space bands inclined, which is used in the preferred embodiment of my invention, is illustrated in the extreme position of FIG. 12. The problem is to insure that lug 47 will engage the rear edge 49 of only the lowermost band in the stack and will not engage either the sleeve edge 49 of the next upper band 51 or the left edge of the body cross piece 21 of this next upper band. With the bands inclined as shown in FIG. 12 it is seen that the path of travel of the uppermost end of lug 47 is along a dotted line 52 so that when the lower band is moved off of the pins 24 and 25 the next band will drop on to these pins but will have a clearance above line 52 equal to the distance 53. This clearance insures that the lug is prevented from engaging the edge of cross piece 21 in case it is bent downwardly or the band is excessively worn so as to create a ragged edge that could be snagged by the feeding lug. In actual practice the bands are inclined only sufliciently to insure feeding of only one band "at a time regardless of their worn or bent condition. Very slight longitudinal movement ofa band will cause its ears 23 to drop off of the relatively narrow pins *24 and 25 thereby immediately causing the band to drop off of the relatively narrow pins 24 and 25 whereupon the band drops completely down over lug 47 so that the latter obtains a good bite on the edge '49 as clearly shown in FIGS. 15 and 16 thereby to facilitate pushing the sleeve (which in turn pulls the band body) beneath the knife 56 and polishing block 57 to be shortly described.

In actual practice the bands are not extremely inclined as shown in FIG. 12 but are preferably inclined a smaller amount as shown in FIG..11. In this case the clearance corresponding in principle to 53 is relatively small but sufficient to have the lug 47 clear the cross piece 21 and at the same time allow this lug to secure a good bite on the sleeve 22 when the band ears drop off the pins 24, 25. Under certain conditions it might be possible to have a zero inclination as shown in FIG. 13, but in this case relatively long ear supporting pins 58 are preferred in order to insure that the carriage lug '47 will be past the rear edge 59 of the body cross piece 21 before the ears 23 drop off of the pins 58, thereby maintaining some degree of clearance between the upper end of the lug 47 and the bottom of cross piece 21. The clearances in this arrangement are so close as to be very critical. Hence, for worn bands the principles embodied in my inclined band as shown in FIG. 12 afford fool-proof operation for all practical purposes.

With a band now securely engaged by the feeding lug 47 it is next pulled, as shown in FIG. 7, beneath a scraping knife 56 and polishing blocks 57. As shown in the bottom perspective of FIG. 14 the knife is formed to engage only one half of one side of the band sleeve 22 such as the area 62/, FIG. 3, where the type metal usually adheres. The polishing blocks 57, FIG. 14, engaging both halves of one side are made of wood or any other sutiable material that will polish the upper band surfaces as they pass under the same. The knife and blocks are mounted in a vertically movable support 63 whose rear end, as shown in FIG. 7, abuts an undercut forward wall 64 of the feeding magazine 1. This support is yieldingly pressed downwardly by a series of springs 65 interposed between the top surface of the support 63 and a stationary frame 66 which extends for substantially the full length of the machine as shown in FIG. 1. To limit the downward movement of the knife and block support 63 a series of screws 68 extend freely downwardly through frame 66 and have adjustable threaded connection with support 63. The upper end of the screws 63 are provided with shoulders 69 serving as stops engageable with the top of frame 66 to limit the downward position of the knife and cleaning blocks while at the same time allowing the support 63 to yield upwardly against springs 65 as a band moves under the knife and the cleaning blocks to raise the same. It is desirable to be able to raise and lower the knife and cleaning blocks to suit different thicknesses of space bands which may be cleaned at any particular time in the machine. Without this arrangement a band of larger thickness would strike the knife edge and damage the same. In my arrangement I am able to have a substantial portion of the sleeve of bands of all thicknesses pass under the knife and then be slightly raised to firmly engage the knife at the area of the typographical metal. To accomplish this adjustment the series of screws 68 are provided with preferably square ends 70 on which small levers, FIG. 1, are mounted. Similar levers are formed on the upper end 72 of nuts 73 in which the springs 65 are seated. Similar springs, and adjusting screws are employed in connection with a vertically yieldable support 75 in which wiping material 76 is disposed. Small levers 77 identical to levers 71 are commonly connected with lever 71 to a longitudinal bar 78. When this bar is shifted longitudinally it causes the levers 71 and 77 to rotate the screws 68 and spring seats 73 so as to raise or lower the supports 63 and 75 and to adjust the pressure of springs 65 thereby to adapt the machine to space bands of different thicknesses. T 0 adjust the bar 78, FIG. 1, a handle 79 has a stationary pivot 80 secured to the frame 66 while a pin 81 pivotally connects the handle to the longitudinal bar 73. The handle may have its other end serve as a pointer to a suitably marked index plate 82 indicating large," medium, and fsmall space bands.

A longitudinal channel 83, FIG. 14, extends throughout the length of support 63 thereby to permit the carriage lugs 47' to pass throughout the length of the machine without obstruction.

The lug 47 pushes on the sleeve 22 thereby causing the body portion 19' of the band to be pulled by the sleeve so as to maintain the band in its fully extended position during the scraping and polishing operation. In order to cause the scraping and polishing pressure to be exerted preferably only on the localized portions of the band sleeve 22 the carriage 31, FIG. 5, is provided with two small raised surfaces 85 which support the band immediately beneath its sleeve on each half thereof in the general transverse plane of the critical area 62, FIG. 3. As the carriage rides up on cam surface 44 the supporting surfaces 45 cause the band to be firmly held against the knife and polishing blocks which. yield upwardly against springs 65.

As the bands move along they pass beneath graphite supply containers 88 which may be operated by the b and lifting a supply valve in the bottom of the containers in a well known manner.

The single continuously moving chain finally discharges the bands into the receiver generally indicated at 3, FIGS. 17-19. As shown in FIG. 17 the chain and sprocket Ill is disposed within a vertical slot 90 which is provided in its side near the top with a pair of inwardly projecting pins 91 whose top surface lies in the horizontal plane of the fiatted top edges of the chain links. The

forward side edges of a band slide over the top of these pins as the band is pulled along over sprocket 10. The carriage lug 4'7 finally moves downwardly to disengage the sleeve edge 49 thereby allowing the body portion of the band preferably to drop a short distance to rest on the horizontal pins 9 1 while the ears 23 will be held a slight distance above a pair of horizontal safety rails 92. The band is held in this partially suspended position by the aid of a cleaning brush 94 under which the band is pulled. The brush thus bears down on the rear end of the band behind the pins 91 which act as a fulcrum to hold the sleeve end of the band free of rails 92. The portion of the band behind pins 91 is supported on the horizontal fiatted top edges of the chain links. The band will thus come to rest at the level shown at 93, FIG. 18. The level 93 is such that the rear end of the band is in the path of the forward end of the following carriage 31. The carriage is provided with a transverse V-groove 95 to engage the rear end of the temporarily stationary band 93, thereby to push the band along until its rear end clears the horizontal 91. At this point the ears 23, as shown in FIG. 17, have been already moved on to downwardly inclined guide rails 96. As the band is pushed off of pins -91 the rear end of the band will swing downwardly, as generally indicated at 97, and slide down to the end of the rail portions 96. The reason for keeping the sleeve ears free of rail 92 is to prevent the sleeve from telescoping in the band body such as might result from sliding friction if the ears were in contact with the rails 92. The rails 92, serve as a safety in case a defective band should accidentally drop before reaching the rails 96. successively discharged bands will accumulate in the semi-circular sheetmetal container 98 until it is filled. To facilitate stacking of the bands in container 9 8 a vertically extending generally triangular shaped guide 9 is centrally disposed within the bottom of the container at its entering end so that the usual notch 160, FIG. 15, in the rear end of the space band will be guided over element 99. The bands may then be removed from thereeeiving receptacle 98 by a suitable hook passed into the group of bands through the slots 20. A handwheel .ltlfi is secured to the front sprocket shaft to drive the chain.

From the foregoing disclosure it is seen that I have provided a space band cleaning machine that requires only a single chain and that the bands may be initially fed by this single chain and continued in motion by it with out any interruption or transfer action of feeding mechanisms such as heretofore required. The inclined bands in the feeding magazine permit the feeding lug of the chain carriages to feed the bands with minimum possibility of two bands being fed at one time which has heretofore arisen where bands are excessively worn or bent. The space band carriages and the knife and polishing elements provide an extremely simple and yet highly effective means for exerting a localized cleaning pressure on a critical sleeve area where the hot typographical metal initially impinges on the sleeve. While the carriages with their feeding lugs and localized pressure supports are especially effective in allowing a single chain to be used, it is to be understood that broadly the carriages are operated by chain means whether of one or more chains.

My improved machine also provides an extremely Simple means for adapting it to bands of different thicknesses while still maintaining the same uniform scraping and polishing pressure on the bands regardless of their different thicknesses. The discharging means of which the single chain and the band supporting carriages are an integral part effectively allows the bands to be stacked in a pendant manner in the receiving container. The arrangement of the receiving container is sufiiciently simple that it is connected to the chain guiding structure 13 by angle irons 104. As a result of these and other features heretofore described I have provided a machine that is relatively simple in construction, operation and maintenance and that has a high degree of effectiveness and freedom from trouble.

it will of course be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. A machine for cleaning space bands having a usual elongated slotted body portion which tapers from a thick rear end to a thin forward end and a sleeve longitudinally slidably supported on the body, the sleeve being provided with ears at its forward end and with a rear edge extending across the body slot comprising, in comination, magazine means for supporting a stack of bands with their sleeves in a forward position, endless chain means extending in the direction of the length of the bands, and a band carriage connected to the chain means, the carriage having means for entering the slot ofthe lowermost band in the stack and engageable with the rear edge of the sleeve thereof to move the lowermost band out of the magazine during movement of the chain means, whereby the chain means and carriage operate in one continuous movement to engage and feed the lowermost band in the stack.

2. The combination set forth in claim 1 further characterized by the provision of means for supporting the bands in an inclined position with their cars at a higher elevation than the other end of the band, whereby the sleeve engaging means of the carriage initially engages said rear sleeve edge at the lowest point of elevation of the sleeve and thereby minimizes the possibility of the sleeve engaging means accidentally engaging any other portion of the next upper band in the stack.

3. The combination set forth in claim 1 further characterized by the provision of a pair of pins upon which the band ears are supported at a higher elevation than the other end of the band whereby the sleeve engaging means of the carriage engages said rear sleeve edge at the lowest elevation of the sleeve, and the supporting pins being of such dimension in the direction of travel of the carriage that the ears drop off of the supporting pins substantially before the end of the remaining stacked bands is reached, thereby to minimize the possibility of the sleeve engaging means having contact with the next higher band in the stack and at the same time insure having the rear sleeve edge of the engaged sleeve extend well down over the sleeve engaging means of the carriage.

4. The combination set forth in claim 1 further characterized in that the chain means comprises a pair of sprockets disposed on axes parallel to each other and a single endless chain running around said sprockets in a vertical plane containing the slots of the stacked bands, one of the sprockets being disposed in the rear of the machine substantially beneath the stacked bands and the carriage being supported directly by the chain with the sleeve engaging portion of the carriage also disposed in said vertical plane whereby as the carriage moves around the rear sprocket it will automatically move into the slot of the lowermost band of the stack and engage the rear edge of the sleeve to carry such lowermost band for- Wardly.

5. The combination set forth in claim 1 further characterized in that the chain means comprises a pair of sprockets disposed on axes parallel to each other and a single endless chain running around said sprockets in a vertical plane containing the slots of the stacked bands, one of the sprockets being disposed in the rear of the machine substantially beneath the stacked bands and the carriage being supported directly by the chain with the sleeve engaging portion of the carriage also disposed in said vertical plane whereby as the carriage moves around the rear sprocket it will automatically move into the slot of the lowermost band of the stack and engage the rear edge of the sleeve to carry the lowermost band forwardly, and guideways extending lengthwise of the chain and into which the carriage is moved so as to be supported by the guide ways.

6. The combination set forth in claim 1 further characterized by the provision of a scraping knife which is yieldable upwardly away from the chain, the carriage having means for supporting the band in a localized area adjacent the sleeve as the band moves out of the magazine means, and a supporting surface along which the carriage moves and having an upwardly inclined portion for raising the carriage upwardly so that the band which is supported on the localized area is pressed against the scraping knife.

7. The combination set forth in claim 1 further characterized by the provision of a scraping knife which is yieldable upwardly away from the chain, the carriage having means for supporting the band in a localized area adjacent the sleeve as the band moves out of the magazine means, and means for adjusting the elevation of the knife structure so that it has any one of a plurality of predetermined minimum elevations above the carriages thereby to allow space bands of different thicknesses to pass under the knife.

8. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands, the receiving chamber having downwardly inclined rails upon which the ears of a band slide and a downward space into which the rear end of the band may fall while being suspended by the sleeve ears on said rails, the chain means causing said carriage to move downwardly out of engagement with the sleeve when it reaches the receiving chamber, means for supporting the band in a horizontal position after the carriage disengages the sleeve, and the carriages having provision so that the next following carriage engages the rear end of the discharged band to shove it forwardly from its horizontal position thereby allowing said rear end of the band to fall downwardly and be supported in a substantially vertical position on the rails solely by its ears.

9. The combination set forth in claim 1 further characterized in that the carriage has at its forward end horizontal surface means upon which the band drops as the band is moving out from its stack.

10. The combination set forth in claim 1 further characterized in that the carriage has means for supporting the band in a localized area adjacent the sleeve as the band is fed from its stack.

11. The combination set forth in claim 1 further characterized in that the carriage has means for supporting the band in a localized area adjacent the sleeve as the band is fed from its stack, and a supporting surface along which the carriage moves and having an upwardly inclined portion for raising the carriage after it feeds a band from the stack.

12. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands, means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, and means for supporting the band in a horizontal position after being disengaged so that the rear end of the band is in the.

path of movement of the next succeeding carriage'which to move it into the receiving chamber.

13. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands, means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, and means for supporting the band in a horizontal position after being disengaged so that the rear end of the band is in the path of movement of the next succeeding carriage which thereupon engages said rear end of the disengaged band to move it into the receiving chamber, said means for supporting the disengaged bands including the upper surface of the chain means upon which the rear portion of the band rests when disengaged.

14. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands, means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, and means for supporting the band in a horizontal position after being disengaged so that the rear end of the band is in the path of movement of the next succeeding carriage which thereupon engages said rear end of the disengaged band to move it into the receiving chamber, said means for supporting the disengaged bands including a horizontal surface upon which the rear portion of a band.

falls when disengaged.

15. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands; said chamber having rails for supporting the sleeve ears and a downward space into which the rear end of the bands fall, while being supported by their ears, when the bands are moved a predetermined distance into the receiving chamber; means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, and means for thereafter moving the band into the receiving chamber.

16. The combination set forth in claim 1 further characterized by the provision of a receiving chamber into which the continuously moving carriages discharge bands, means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, means for supporting the band in a horizontal position after being disengaged so that the rear end of the band is in the path of movement of the next succeeding carriage which thereupon engages said rear end of the disengaged band to move it into the receiving chamber, and means for yieldingly pressing down on the band while it is in said horizontal position.

17. The combination set forth in claim 1 further characterized by the provision of a receiving chamber, into which the continuously moving carriages discharge bands, means for causing a carriage to disengage a band sleeve when the band reaches the receiving chamber, means for supporting the band in a horizontal position after being disengaged so that the rear end of the band is in the path of movement of the next succeeding carriage which thereupon engages said rear end of the disengaged band to move it into the receiving chamber, said means for supporting the disengaged bands including the upper surface of the chain means upon which the rear portion of the band rests when disengaged, and a brush disposed above the disengaged band in engagement therewith so as to press downwardly on the band so as to clean it and also assist in holding the band in its horizontal position.

References Cited in the file of this patent UNITED STATES PATENTS 945,870 Scovill Jan. 11, 1910 1,901,281 Bower Mar. 14, 1933 2,231,196 Romyns Feb. 11, 1941 2,688,413 Donehower Sept. 7, 1954 2,731,131 Shannon Jan. 17, 1956 

